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Growing tomatoes is a bit like fishing - everyone has a story! Talking to experienced gardeners is a great way to learn new tricks, but as all those stories indicate, there are lots of pathways to the perfect tomato.

However you go about it, no tomato is as satisfying as one from your own garden. And despite all that talk, tomatoes are very easy to grow.

Gardener's Choice

The choice of tomato varieties can be overwhelming. In recent years gardeners have been rediscovering what we call the 'heirloom' varieties, which have been around for at least fifty years, sometimes hundreds, and passed down through generations. Some of them, such as Money Maker have never gone out of favour.

If you are bored with plain red tomatoes, look to the heirlooms for a wonderful assortment of colours and interesting shapes. Some heirloom varieties have a high proportion of foliage to fruit but because the sugars and acids that make up the flavour are made in the leaves, the payback is in the taste. In general, heirloom varieties have good disease resistance, although each performs differently depending on where they are grown and seasonal weather conditions.

Trialing an assortment of different varieties is the best way to work out which are best for you and your garden.Plus there are also many excellent modern tomato varieties.

Reliable NZ favourites

  • Sweet 100 - long trusses bear up to 100 small sweet tomatoes, full of flavour.
  • Russian Red - reliable heavy cropper for a wide range of climates.
  • Roma - low acid, pear shaped tomato, popular Italian style.
  • Money Maker - a time honoured (1897) heavy cropper. Tasty and disease resistant.
  • Big Beef - Prolific crop of large fruits with old-time tomato flavour. Disease resistant.

Tomato Basics

Warmth and sunshine

Tomatoes need warm frost-free weather. Unless you have a glasshouse it's risky to plant before the last expected frost, but make the most of the growing season by getting them in well before Christmas. Choose a position sheltered from cold winds. Some air movement is important however, because still humid air invites disease.

Good soil

Tomatoes need a well-drained soil and a non-stop supply of water and nutrients. Prepare the soil by digging in lots of compost and some balanced general fertiliser. High potassium tomato fertilisers aren't recommended until flowering starts, as high potassium levels may actually hinder the early green growth by blocking nitrogen.

If you're planting where tomatoes grew last year, dig out the soil and replace it with fresh compost and soil from elsewhere in the garden. Don't plant tomatoes in soil that carried a crop of potatoes, peppers or eggplants the previous year - they're all in the same family and subject to the same diseases.

Planting time

In warm climates start your tomatoes from seed in September, but the easiest way is to buy a punnet of seedlings or individually potted plants from the garden centres in October. Place stakes at planting time to avoid damaging the roots later. Water new plants an hour or so before planting. Water again after planting and finish off with organic mulch to conserve moisture.

Tomatoes from seed

Growing tomatoes from seed means a greater choice of varieties, but one packet produces a lot of plants. Swap varieties with friends to get a better range.

  1. In spring or early summer, sow seed in a tray of seed raising mix. Place the tray in a warm sheltered place, away from frost, and keep the mix just moist.
  2. When seedlings emerge, thin to give them more space (about 5cm apart) or, one week after germination, prick them out into individual pots, taking care not to damage the roots.
  3. When the danger of frost has passed and seedlings are about 15cm tall, with at least four strong leaves, plant them out into the garden.

Plant seedlings deep so the seed leaves are buried. The stem in the soil will send out roots to anchor the plant and seek more food and water.

Keep feeding

Tomatoes love to be fed. The easiest way to be sure of the best balance of nutrients, is to use a fertiliser especially made for tomatoes. These fertilisers have optimum potassium levels to promote fruiting. When the small green fruit make their appearance, start fortnightly feeding with liquid fertiliser.

Home made brews from comfrey leaves (high in potassium) and seaweed are very effective, but care is needed not too make these too concentrated. Sheep pellets and fish manures also give good results. Seaweed makes excellent mulch.

Water wisely

Thoroughly soak the ground at watering time. Training roots to grow deep into the soil via deep but less frequent watering, combined with mulching to keep moisture in, means you'll need to water less often. To avoid disease, aim for the roots, not the foliage.

Tomato Training

Tall growing varieties that produce fruit continuously over many weeks (called indeterminate) are best trained on stakes or wires to encourage manageable upright growth. Remove the little side shoots (called laterals) that appear between each leaf and the main stem. Do this every few days as the plant grows, lightly tying the new top growth to the stake with flexible ties. Guard against disease entry by removing laterals only on a dry sunny day.

When the plant has reached the desired height, or has a dozen or so good trusses of fruit, remove the growing tip at the top of the plant. This diverts energy back into the developing fruit. Although the plant needs its foliage to make energy for growing fruit, removing lower leaves helps promote air circulation.

Dwarf tomato varieties yield one main crop all at once (called determinate). They'll produce more fruit without pruning, but foliage that becomes diseased or overcrowded should be removed. Protect the fruit from contact with the soil by mulching with straw. Alternatively, grow them in containers.

Harvest time

Tomatoes are ideally ripened on the vine. However, harvesting fruit before it is fully coloured helps keep the fruit firmer for longer and relieves the plant of it's load, allowing it to keep on the job of producing more crops. Pick whole trusses, leaving stems intact and place them indoors, away from direct sunlight but not in the fridge, to allow full development of the sugars.

Too many tomatoes? If you grow more tomatoes than your family, friends and neighbours can eat fresh, store all that goodness and flavour for winter. Tomatoes can be dried, bottled or frozen. Make tomato relish to give away, and delicious pasta sauces for the freezer.

Did you know? Cooked tomatoes (in paste, soups, and sauces) and sun-dried tomatoes are even better for us than fresh tomatoes because they're a more concentrated source of the cancer-fighting antioxidant lycopene. Lycopene is what makes tomatoes red.

Tomatoes in Containers

Where soil space is limited, tomatoes are easily grown in containers. One of the most important things you can do to ensure tomato success is to use a big enough container - the bigger the better.

Plastic grow bags are effective and practical. Dwarf and cherry tomatoes, which don't require staking, are well suited for containers or large hanging baskets. Taller varieties can be grown in large pots with support from a climbing frame or stake.

Pay special attention to feeding and watering when growing tomatoes in containers.

  • Tomatoes grown in containers may need water every day or even twice a day,during the hottest days of summer.
  • Water in the morning so your container tomatoes have a chance to dry off before nightfall.
  • Water until you see water coming out the drainage holes, then stop.
  • Water with liquid plant food every week, and use slow release fertiliser granules as well, according to instructions.

Harvest container tomatoes frequently to relieve the branches of weight and encourage the plants to continue blooming and set more fruit.

Natural disease prevention

In warm humid conditions tomatoes attract a range of diseases, but you can grow them without chemicals, or at least minimise spraying by paying attention to soil, water and feeding for strong vigorous growth and taking some preventative measures:

  • The more diverse your varieties, the better. Start with a selection of disease resistant varieties. Grafted tomatoes grow on disease resistant rootstock.
  • Don't plant tomatoes in the same soil in consecutive years. Also avoid soil that has previously grown potatoes or capsicums.
  • Remove tomato laterals on a dry day and use clean hands.
  • Remove lower leaves if they become diseased. Removing lower leaves also helps with air circulation. Use sharp, clean secateurs.
  • Apply Copper spray when removing laterals or cutting off leaves.
  • Avoid overhead watering, which increases humidity and promotes disease.
  • Apply water at ground level.
  • Don't plant too closely.
  • Mulch to cut down on watering and slow weed growth. Weeds encourage disease!
  • Buy fresh seed or seedlings from a reputable supplier. Seed saved from an infected crop may carry over disease to the next crop.
  • Choose early ripening varieties to avoid the more humid conditions of late summer.
  • In wet humid summers, spray with copper to prevent disease.
  • Plant good companions: basil, marigolds, calendula, garlic, chives and spring onions help keep tomatoes healthy.

Fresh Tomato Salsa

  • 8 medium vine ripened tomatoes, chopped
  • 1 tablespoon finely chopped red onion
  • 1 red chilli, finely chopped
  • 2 tablespoons fresh lime juice
  • 2 tablespoons chopped coriander
  • 1 tablespoon olive oil
  • 1 teaspoon honey
  • salt and freshly ground black pepper

Combine first 7 ingredients in a bowl then season to taste with salt and freshly ground black pepper.


Look for these products, tips and advice at a Go Gardening Store near you.



A truss of ripening tomatoes, planted with companion sweet basil.